The Urban Wildlands Group, Los Angeles, California, United States of America.
PLoS One. 2012;7(4):e34025. doi: 10.1371/journal.pone.0034025. Epub 2012 Apr 25.
Avian mortality at communication towers in the continental United States and Canada is an issue of pressing conservation concern. Previous estimates of this mortality have been based on limited data and have not included Canada. We compiled a database of communication towers in the continental United States and Canada and estimated avian mortality by tower with a regression relating avian mortality to tower height. This equation was derived from 38 tower studies for which mortality data were available and corrected for sampling effort, search efficiency, and scavenging where appropriate. Although most studies document mortality at guyed towers with steady-burning lights, we accounted for lower mortality at towers without guy wires or steady-burning lights by adjusting estimates based on published studies. The resulting estimate of mortality at towers is 6.8 million birds per year in the United States and Canada. Bootstrapped subsampling indicated that the regression was robust to the choice of studies included and a comparison of multiple regression models showed that incorporating sampling, scavenging, and search efficiency adjustments improved model fit. Estimating total avian mortality is only a first step in developing an assessment of the biological significance of mortality at communication towers for individual species or groups of species. Nevertheless, our estimate can be used to evaluate this source of mortality, develop subsequent per-species mortality estimates, and motivate policy action.
在美国和加拿大，内陆通讯塔上的鸟类死亡率是一个紧迫的保护问题。此前对这种死亡率的估计是基于有限的数据，而且没有包括加拿大。我们收集了美国和加拿大内陆通讯塔的数据库，并通过将鸟类死亡率与塔高相关的回归来估算每个塔的鸟类死亡率。该方程源自 38 项具有死亡率数据的塔研究，并针对抽样力度、搜索效率和适当的清道夫效应进行了校正。虽然大多数研究都记录了带有稳定燃烧灯的架空塔的死亡率，但我们通过调整基于已发表研究的估计值，考虑到了没有拉索或稳定燃烧灯的塔的死亡率较低的情况。在美国和加拿大，由此产生的塔上死亡率估计值为每年 680 万只鸟类。引导式抽样表明，回归对所包含研究的选择具有稳健性，而且对多个回归模型的比较表明，纳入抽样、清道夫效应和搜索效率调整可以提高模型拟合度。估计鸟类的总死亡率只是评估通讯塔对个别物种或物种群体的死亡率的生物学意义的第一步。尽管如此，我们的估计可以用来评估这种死亡率来源，制定后续的每种鸟类死亡率估计值，并推动政策行动。
